Stefanie Barz

Secure delegated computing is a key task for both classical and quantum networks. There exist both classical and quantum protocols for performing secure (quantum) computations in networks. In this talk, I will first give an overview of secure delegated quantum computing. Here, a client with no quantum-computational power can delegate a quantum computation to a fully fledged quantum server. I will particularly focus on experiments and vulnerabilities in the implementations. Further, I will focus on the interplay of classical and quantum approaches for delegated computing. I will demonstrate a way to perform classical (multiparty) computing amongst parties with limited computational resources. Our method harnesses quantum resources to increase the computational power of the individual parties. As particular examples, I will show how a client restricted to XOR gates can perform universal classical computation using single qubits. Further, I will demonstrate how a set of clients restricted to linear classical processing are able to jointly compute a non-linear multivariable function that lies beyond their individual capabilities. Finally, I will show proof-of-concept implementations using photonic qubits. Thus, this work highlights how minimal quantum and classical resources can be combined and exploited for classical computing.